This invention relates to motor vehicles, and more particularly to improvements for three-wheel motor vehicles. These improvements include a tilting mechanism, suspension system, safety frame, sliding door feature and overall improvements in aerodynamic design.
Currently, most motor vehicles on the highways are four-wheel vehicles which are usually larger, heavier and less fuel efficient than three-wheel motor vehicles. Perhaps the reasons that three-wheel vehicles have not caught on is because the public is not aware of the advantages of three-wheel vehicle design. Three-wheel vehicles by nature are more stable than four-wheel vehicles since three points will form a plane under all circumstances, such as seen in a tripod, whereas four points do not. This stability is recognized by the fact that practically all aircraft and space shuttles employ three-point landing gears. Another advantage is that three-wheel vehicles afford nearly ideal wheel loading for maximum tire traction in acceleration and braking situations.
Although a three-wheel motor vehicle may have numerous advantages over four-wheel vehicles, the main drawback of a three-wheel vehicle is that during a turn the centrifugal load of the vehicle is supported by only one wheel rather than two. The centrifugal force tends to overload the outside tire and causes the vehicle to sideslip away from the direction of the turn unless some means of compensation is provided. The one means of compensation is a tilting-and-bank mechanism, which shifts the car's center of gravity to the inside keeping more load on the inside tire.
Numerous prior U.S. patents have disclosed tilting mechanisms, but none like the present invention. For instance, U.S. Pat. No. 4,377,215 dated Mar. 22, 1983 by Hare, shows a substantially three-wheel vehicle which is tilted by a mechanical linkage from the steering column to lever arms. The body and frame tilt while the wheels remain vertical at all times. No hydraulic or electrical means for tilting is provided.
U.S. Pat. No. 4,373,743, dated February by Parsons, Jr., also provides a mechanical tilting mechanism. U.S. Pat. No. 4,550,926 dated Nov. 5, 1985, by MacIsaac, shows a vehicle- suspension system that allows the body and wheels to tilt to the inside of the curve by placing the center of gravity of the body and frame below the vehicle roll center.
Another U.S. Pat. No. 3,746,118, by Altorfer, dated Jul. 17, 1973, utilizes mercury switches activated by electrical switches to energize an electro-actuator to bank a three-wheel vehicle. However, mercury switches are sensitive to road vibrations and are thus not fit to be used for banking purposes.
U.S. Pat. No. 4,600,216 by Burkholder, dated Jul. 15, 1986, provides a steering linkage which rovides for banking in a three-wheel vehicle having two wheels in the front.
Another U.S. Pat. No. 4,624,469 by Bourne, Jr., dated Nov. 25, 1986, shows a three-wheel vehicle which uses a rod between the wheels that rotates through a ninety-degree arc thereby allowing turning and banking at the same time. This vehicle has two front wheels and not one wheel as does the present invention.
Another three-wheel vehicle is shown in U.S. Pat. No. 4,717,164 by Levavi, dated Jan. 5, 19. Contrary to the present invention, it also has two wheels in the front and one in the back and uses manually-actuated hydraulic cylinders to bank the vehicle in turns.
Finally, U.S. Pat. No. 2,787,473, by Chiodo, dated Apr. 2, 1957, discloses a hydraulic stabilizing system for a four-wheeled vehicle.
Although the above-patented inventions have attempted to resolve the problems in turning associated with three-wheel vehicles, the present invention uses an engine driven hydraulic pump to pressurize the hydraulically-operated system to automatically tilt the entire vehicle in a turn, slanting the wheels inwardly in a curve similar to that of a motorcycle. Although a motorcycle with rider usually has a combined higher center of gravity than most automobiles, a motorcycle maintains perfect balance and traction through a turn due to the resultant vector of gravitational and centrifugal forces being balanced by the shifting weight of the rider, which means that the resultant force is constantly applied through the centerline of the combined rider-motorcycle mass. The tilting system of the present invention closely simulates this balancing act by use of either a manual, automatic electro-mechanical or automatic mechanical hydraulic control and actuating system. This tilt system requires only the rear wheels to be raised or lowered hydraulically while the single front-wheel tilts with the body.
Another feature provided by the present invention not present in other three-wheel vehicles is the safety frame. Many types of frames in the prior art have disclosed frames, some with wrap-around structure and some with roll-bars, but none like the present invention. Amongst those U.S. patents are the following: U.S. Pat. No. 4,045,075 to Pulver dated Aug. 30, 1977; U.S. Pat. No. 4,453,763 to Richards dated Jun. 12, 1984; U.S. Pat. No. 2,507,421 to Rose dated May 9, 1950; U.S. Pat. No. 2,612,964 to Hobbs dated Oct. 7, 1952; and U.S. Pat. No. 3,575,251 to Moore dated Apr. 20, 1971.
The safety-frame design of the present invention is novel because it combines a wrap-around bumper with longitudinal tubes on the sides and top with three roll bars and connectors. Plus, the football shape of the vehicle safety frame increases the likelihood that any collision will result in a glancing blow to the vehicle rather than direct hit. Should the vehicle be struck, the blow would be deflected in such a manner that the passengers would remain safe. Further, should the vehicle roll over, the roll-bar construction will completely protect the occupants.
Another problem associated with not only three-wheel vehicles, but also most other automobiles is that associated with opening doors. Most doors swing out and hit other cars or walls and prevent the doors from being opened fully when other cars are parked too close. The prior art includes some designs which might resolve this problem comprising sliding doors such as those contained in U.S. Pat. No. 2,955,872, by Barentyi, dated Oct. 11, 1960; U.S. Pat. No. 3,594,036, by Cadiou, dated Jul. 20, 1971; and U.S. Pat. No. 3,550,948, by Thompson, Jr., dated Dec. 29, 1970. However, the present invention provides for lifting and rolling doors, which move up, back and down through a low arc off of and onto rain seals on the body which seal the vehicle when it is raining. In addition to having the advantage of rolling back and forward, these doors can also be opened partially to provide ventilation for the occupants of the vehicle.
In addition to the above specific features, the present invention also provides a novel aerodynamic body design not found in any other vehicle design. The body of the present invention is designed to incorporate the downward force of an inverted wing with the minimal drag of an airfoil. The design contains a pointed nose, upswept tail, front air dam, and full belly pan and flush glass, which all contribute to improved road holding and a significant reduction of aerodynamic drag and fuel consumption.
Another feature of this invention is the front wheel suspension design which places the king pin ahead of the wheel for improved caster control allowing the vehicle to recover from a turn and maintain straight line travel with greater ease and precision.
The forward king pin also allows the front wheel to swing to the outside in a curve, thus counteracting the overturning centrifugal load by moving the wheel out from the longitudinal center line of the cars front mass and at the same time placing the mass to the inside of the tire patch.
The forward king pin also permits the front of the car to be swung in and out of a parking space faster and with less effort and effectively lengthens the wheel base for a better ride.
Thus, the present invention provides novel systems and designs which alleviates various problems associated with previous designs of three-wheel vehicles, thereby making it possible to build safe three-wheel motor vehicles for widespread passenger use.
The aim of the present invention is to provide a safer three-wheel vehicle for regular highway use.
Another object of the present invention is to provide a safe tilt-and-bank suspension system that will enable three-wheel vehicles to take corners at high speed.
Even another object of the present invention is to provide a safer suspension system for the front wheel that will enable the front wheel to bear centrifugal loads and grip the road better during turns.
A further object of the present invention is to provide a space frame for a three-wheel vehicle that greatly increases the safety of the occupants.
Even another object of the present invention is to provide a design for a three-wheel vehicle that is more aerodynamically efficient and safer from having greater downforce, thus better traction and road handling than present designs.
An additional object of the present invention is to provide a roll back vehicle door, able to remain open while driving to give a convertible effect to the occupants, and which enables the vehicle to be parked in smaller places.